The invention relates generally to a power management control system and in particular, to a power management control system that implements the Utility Communications Architecture (UCA).
In today's power management control systems, a variety of power monitoring or control devices are connected to a common bus which allows the power monitoring or control devices to communicate with a server. One standard protocol used for communicating between the server and the power control and monitoring devices is the Modbus RTU standard. There are many Modbus RTU/DDE Servers commercially available for a wide variety of applications. All major electrical distribution companies have a similar product. The narrow scope of these servers are their major limitation. These systems expect the client applications (Man-Machine Interfaces) to handle the complexities of the actual power controlling and metering devices. Many of the servers are designed to communicate using a protocol designed for use with only certain devices, family of devices or specially designed devices. Also, not all the servers are able to support any generic Modbus RTU compliant device.
An improvement over such power management control systems is described in U.S. Pat. No. 5,862,391 entitled "power Management Control System." The power management control system described therein comprises a computer having standard RS485 interface cards and adapters installed in its I/O slots defining multiple industry standard Modbus RTU networks. Devices with a Modbus RTU interface can be connected directly to the Modbus and other devices which communicate on the Commnet protocol require a Modbus concentrator. The Modbus concentrator provides an interface between the Modbus RTU protocol and the Commnet protocol, whereby these other devices can communicate through the Modbus concentrator over the Modbus. Alternatively, standard Ethernet interface cards and adapters are installed in the computer's I/O slots defining multiple standard Ethernet TCP/IP networks. The Ethernet TCP/IP protocol is a well known standard, which would allow a user of the power management control system of the present invention to use its existing LAN. Ethernet gateways are connected to the Ethernet TCP/IP networks to provide an interface between the Ethernet TCP/IP protocol and the Modbus RTU protocol.
The Utility Communications Architecture (UCA), developed by the Electrical Power Research Institute (EPRI), provides a flexible and scaleable computer communications architecture for communication within and among control systems in the electric, gas, and water utilities. The UCA, currently under Version 2, is a suite of existing technologies and standards, which includes an Ethernet physical layer, a Transport Control Internet/Internet Protocol (TCP/IP) or International Organization for Standards Open Systems Interconnect (ISO-OSI) network layer, and a Manufacturing Message Specification (MMS) application layer. MMS is an internationally standardized messaging system for exchanging real-time data and supervisory control information between networked devices and/or computer applications in a manner that is independent of the application that is being performed or the developer of the device or application. UCA Version 2 provides many beneifits to a control system, including interoperability between different vendors over the same communication network, and rapid installation due to self-defining, object oriented data objects.